Waterproof abrasive



Patented Jan. 25, 1927.

' UNITED STATES e if, ism 311' -PATENTJQF ICEQ- nnnarn. rownia, or NIAGARA FALLS nnw roux, ASSIGNOB no rain cmonun nU-m company, or NIAGARA rants, new your, A coaronarron or rmsrng VANIA.

No Drawing.

My invention relates to waterproof abra sives, and particularly to the waterproofing of abrasive paper and cloth.

Abrasive 1 paper or cloth is ordlnarlly made by applying)a coating of hot adhesive,-

such as hide glue, one glue, or vegetable glue, to the surface of the backing, then runn ng on a stream of abrasive grain, and allowing the product to cool. The ordlnary adhesives in use for this purpose are not waterproof and do not permit of the efficient use of the abrasive paper with water WlllCh is required in the process of rubbing certain kinds of varnish finish. The water loosens.

paper and materially on both the face and the back of the abrasivc paper or cloth. The waterproofing substance'is preferably yroxylin dissolved in a proper solvent, suc as an acetate llke butyl acetate, with or without other acetates, an alcohol like ethyl alcohol, with or without other alcohols, ketones. like acetone, methyl ketone or acetone oils, benzol, and camphor. I find it possible to use in the solution of nitro-cellulosea "guni, such as copal or damar. The solution mentioned may vary within wide limits, and should be adjusted as 'to its boiling point to prevent too ra id evaporation of the film and to re-- vent a sorption of water which may wea en.

the film before it is set.

In order to get a form of nitro-cellulose which can be used in solution and possess properties essential for operation on a production basis, such as even flowing or spreading on the backing used, there must bea certain balance of hi h, medium, and low boiling solvents to o tain the proper rate of evaporation. To get the gum, like damar, into solution, and the nitro-cellulose into solution, the lower boiling solventsfsuch as ethyl alcohol, acetone and an acetate. are used. To prevent too rapid evaporation warnnrnoor annasrvn, 7

Application filed June 2 1, 1923. Seliallfi'o. 646,958. I

and thus provide for the proper flow of the material, additional solvents of relatively higher boiling points, such as butyl and amyl acetates, the higher boiling alcohols, and certain ketones are used, Low evaporation rate, produced by higher boiling solvents prevents cooling of thesurrounding air and the consequent condensation of water on the lacquer surface. This in turn prevents precipitation of the nitrocellulose.

Thus the important adjustment of the solution to the proper boiling point is secured.

nent.

The function of the gum is to give adhesion, body and hardness to the coating and to render the coating more imperious to moisture. This increase in the hardness of the film is a very desirable feature in producing a good abrasive paper because the abrasive grains on the paper undergo very severe service in the art of rubbing or grinding the materials on which they are being worked, and by increasing the hardness of the film the grains are more firmly held in place and stick on to the backing icnger and more securely so that the iife 0f the abrasive article is increased. The gum also increases the body of the coating material without increasing the viscosity thereof, and this is 'highl desirable. Being cheaper than nitro-cel ulose, many gums tend to reduce the cost. In increasing the hardness by the use of a gum there is a tendency to brittleness, and to offset this and secure plasticity is one of the functions of the plasticizer,-such as camphor.

On the evaporation of the solvent from V the abrasive product, a thin transparent film is left which protects the adhesive from the action of water, even under very severe conditions.

Another method of carrying out the invention is to apply the nitro-cellulose solution to the paper or cloth backing in the same manner as the glue is commonly applied, and then fiow the abrasive grain ereon. The product is then run over or under are recovered.

The film of abrasive and adhesive on the paper or cloth may then be put into use or sized with a thin yroxylin solution to hold the grains more rmly in place. I provide an abrasive which is resistant to the action of water andwhich may be used under very severe conditions.

It will be noted that in either case, there is an outer coating of nitro-cellulose which not only serves to waterproof the abrasive product, but is also effective for assisting to secure the rains in place.

The word fabric'is used in the claims to designate a flexible backing of paper or cloth, such as is employed in the manufacture of sandpaper or sandcloth.'

While I have described bodirnent of my invention, it will be undertaining a stood that it is not limited thereto but may be otherwise embodied withinv the. scope of the following claims.

-I claim 1. An abrasive product comprising a flexible backing having abrasive grains attached thereto by a nitro-cellulose composition containing a gum.

2. An abrasive product comprising a flexible backing having abrasive grains attached thereto by a nitro-cellulose composition conm and a plasticizer.

3. An a rasive product comprising a flexible backing having abrasive grains attached thereto by a nitro-cellulose composition, including an acetate, an alcohol, a ketone, benzol, 'a plasticizer, and a gum.

4. An abrasive product comprising a flexible backing having abrasive grains attached thereto by a nitrocellulose binder containin an acetate, an alcohol, a ketone, ben- 5. An abrasive product comprising a flexible backing having abrasive grains attached a preferred em thereto by a intro-cellulose composition containing an acetate, an alcohol, a ketone, a benzol-type hydro-carbon, and a plasticizer.

6. An abrasive product'comprising a flexiblebacking having abrasive grains attached thereto by a nitro-cellulose composition containing a solvent, camphor, and a gum.

7. An abrasive product comprising a flex- 4 cellulose, a high boiling solvent, a low boil ing solvent, a plasticizer, and a gum.

10. Anabrasive product comprising a flexible backing having abrasive grains attached thereto by a nitrocellulose composition containing intro-cellulose, a guru for giving body to the nitro-cellulose and a substance for rendering the composition tou h and permanent and for overcoming the iflltillfiness of the gum.

11. An abras1ve product comprising a fle2rible backing having abrasive grains attached thereto by a flexible film containing nitrocellulose, a. gum for giving body to the nitro-cellulose, and a plasticizer for rendering the film flexible, tough and permanent.

12. An abrasive product comprising a flexible backing having abrasive grains attached thereto by a film which is resistant to water, such film being deposited from a slow evaporating nitro-cellulose composition in solu tion with a low boilin solvent, a high boiling' solvent for retar ing the evaporation thereof and by which an even spreading of the film is secured, a gum for giving body to the composition, benzol, which forms a solvent for the gum, and a plasticizer for imparting permanent toughness and flexibility to the film.-

In testimony whereof I have hereunto set my hand.

I HENRY R. POWER. 

